When a Lookup Field is configured to return either a Single Select or Multiple Select field, a count Field fails to allow the count of the returned values.
In the screenshot below, Count should allow the return of the number, 3, 4 and 2.
A current workaround of a Rollup Field seems to work, but it's not as convenient/easy to setup as a designated Count field could be - and may bring a performance hit on larger tables.